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Originally published at Internet.comSpeedStep -- It Isn't Just for Notebooks Anymore
On June 21, Intel Corp. ushered in a new generation of desktop PCs with its 915P, 915G, and 925X Express motherboard chipsets, supporting DDR-2 system memory and the PCI Express successor to the old PCI input/output and AGP graphics interface, as well as new LGA775-socket variants of the Pentium 4 processor. On June 28, it was workstations' turn.
Intel's new workstation platform combines the single- or dual-processor E7525 chipset (formerly codenamed "Tumwater") with new Xeon CPUs (formerly codenamed "Nocona") that mark the Xeon's transition from 0.13-micron to 90-nanometer process engineering, just as the Pentium 4 "Prescott" did in February. The new Xeons also catch up to the Pentium 4's 800MHz front-side bus, boosting throughput over their predecessors' 533MHz bus.
Ironically, the feature that users will probably find most interesting is the one Intel talks about least: The new 2.8GHz through 3.6GHz Xeon processors mark the debut of Intel's Extended Memory 64 Technology (EM64T), which enables 64-bit memory addressing -- ending what the chip giant's formerly nice, neat plans specified as a monopoly on 64-bit computing for its Itanium server CPUs, and a clear distinction between those chips and the Xeon family's venerable 32-bit x86 architecture. In other words, EM64T is Intel's grudging adoption of the AMD64 x86 extensions pioneered by its rival's Opteron processor in April 2003.
New Memory, New Graphics
Given the new 800MHz system bus, you might expect the E7525's dual-channel memory controller to support DDR400 memory as current P4 platforms do, but it stops at DDR333 -- a step up from the E7505 chipset's DDR266, but short of an ideal match for available memory bandwidth. However, Tumwater also supports DDR-2/400 memory, yielding 6.4GB/sec of bandwidth -- according to Intel, up to a 20-percent increase over DDR333 with up to a 40-percent decrease in power consumption.
If memory bandwidth is important to 3D CAD and digital-content-creation workstation customers, graphics bandwidth is even more important. So the E7525 chipset includes a PCI Express x16 graphics interface, delivering 8GB/sec (4GB/sec in each direction) of bandwidth for a variety of third-party PCI Express graphics solutions.
ATI Technologies has added four PCI Express members to its FireGL workstation graphics processor family: the FireGL V3100 and V3200, each with four pixel pipelines, two geometry engines, and a 128-bit memory interface; the FireGL V5100, with 12 pipelines and 128MB of memory; and the FireGL V7200, with 16 pipelines and 256MB of memory. Each of the latter two incorporates six geometry engines and a 256-bit memory interface.
Nvidia Corp. counters with the Quadro NVS 280 for professional 2D applications and Quadro FX 330, Quadro FX 1300, and Quadro FX 3400 for 3D. The FX 330 has a 64-bit memory interface and 64MB of DDR; the FX 3100 has a 256-bit memory interface and 128MB of DDR; and the flagship FX 3400 combines a 256-bit memory interface with 256MB of G-DDR3 memory.
For other I/O, the E7525 chipset also provides a PCI Express x8 interface that can be split into two x4 interfaces. Intel's 6700PXH is a 64-bit PCI hub that offers PCI or PCI-X bus interfaces; the chipmaker also offers a choice of two I/O controller hubs for Tumwater, both supporting dual Serial ATA controllers, four USB 2.0 ports, and 32-bit PCI connectivity and one adding 64-bit PCI-X. The E7525 is priced at $100 in 1,000-unit OEM quantities.
The 90-nanometer Xeons -- which have OEM prices of $209 (2.8GHz), $316 (3.0GHz), $455 (3.2GHz), $690 (3.4GHz), and $851 (3.6GHz), the last availablle in limited quantities until the third quarter -- feature 16K of Level 1 and 1MB of Level 2 cache, like their Pentium 4 Prescott cousins. (The last is actually a step down from the 2MB of L2 cache found on the 3.2GHz flagship of the 0.13-micron, 533MHz-bus Xeon line.) They use previous Xeons' 604-pin PPGA packaging, not the new LGA775 socket of the latest Pentium 4 chips.
In addition to Intel's Hyper-Threading multitasking technology -- which makes compatible software running on a uniprocessor or dual-processor workstation act as if it's on a two-way or four-way system, respectively -- the 800MHz-bus Xeons support SSE3 streaming multimedia instructions.
The 3.4GHz and 3.6GHz models add a feature you're used to hearing about for Intel's notebook chips: Intel's Enhanced SpeedStep Technology, which adjusts CPU clock speed and hence power consumption based on application requirements. In the Xeon's case, SpeedStep forms part of what Intel calls Demand-Based Switching, which enables real-time dynamic shifts between frequency and voltage points, changing the internal core frequency without affecting the front-side bus. It's more likely to impact a server room's electric bill than an individual workstation
New Systems Are Here; New Software Isn't
Nor, at least for the next few months, should users see much impact from Extended Memory 64 Technology, Intel's phrase for 64-bit extensions to its IA-32 implementation of x86 architecture -- which, the company hastens to point out, already has Intel-created enhancements like SSE3 and Hyper-Threading.
Putting a brave face on what's basically an AMD-created enhancement, Intel says the EM64T-enabled Xeon -- expected to be joined by EM64T-enabled Pentium 4 processors this fall -- gives IT managers a new workstation and server option, still positioned firmly below the Itanium family and its x86-incompatible IA-64 or EPIC architecture. The latter remains Intel's preferred platform for mission-critical enterprise work on big multiprocessor servers or other systems where scalability and floating-point performance are supreme.
Technically, EM64T keeps Intel's classic operating mode for 32-bit operating systems and applications while adding a second operating mode called IA-32e, which in turn offers two submodes -- a "compatibility mode" that lets a 64-bit OS run unmodified 32-bit software, and a "64-bit mode" that lets a 64-bit operating system run programs written specifically to access 64-bit address space. The 64-bit OS in question is likely to be Microsoft's Windows XP 64-Bit Edition for 64-Bit Extended Systems, scheduled to ship toward the end of this year, although Red Hat, SUSE, and other Linux vendors should deliver EM64T support sooner; a compatible BIOS and software drivers will be required as well as an OS.
Intel's official Q&A says that "in most cases" it should be possible to write software that runs on both EM64T and AMD64 processors, with the close similarity of the instruction-set architectures overcoming the different hardware microarchitectures involved. Naturally, the company urges developers to use Intel software tools and design specifically for Intel -- and at presstime, The Inquirer had reported that an early E7525-chipset, dual-Xeon/3.4 system failed to run the evaluation version of Win XP 64E now being used by Opteron and Athlon 64 owners, with Intel's implementation apparently optimized not just for running 64-bit code but for systems that physically have more than the 4GB of memory that's the addressing limit for 32-bit processors. Stay tuned.
Dell and HP Get On Board
Two workstation warriors wasted no time in announcing new systems based on the E7525 chipset and EM64T Xeon processors. Dell's Precision 470 (starting at $1,399) and Precision 670 (starting at $1,699) are dual-processor-capable systems available with a variety of PCI Express graphics cards, both SCSI and Serial ATA RAID storage solutions up to 800GB, and DDR-2/400 memory; the 470 has a smaller, rackable chassis while the 670 has more room for storage and peripherals expansion. They're initially available with 32-bit Windows XP Pro or 32- or 64-bit Red Hat Enterprise Linux.
HP's dual-processor Workstation xw8200 (pictured; starting at $1,799) and xw6200 (starting at $1,399) also combine the 800MHz system bus with DDR-2/400 memory and PCI Express graphics. HP says the midrange xw6200 has the most compact dual-CPU form factor available, while the xw8200 can be loaded with up to 16GB of RAM (when 2GB DIMMs become available) and 1.5TB of internal storage. Next month, HP will add an entry-level Workstation xw4200 combining Intel's 925X Express chipset with a single Pentium 4 processor (up to 3.6GHz), PCI Express, and DDR-2; it's expected to start at
Author: Eric Grevstad
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